Hundreds of thousands of people in California have fled their homes as fierce brush fires burn out of control and were predicted to worsen today.

The California governor, Arnold Schwarzenegger, declared a state of emergency and said it was a "tragic time" for the state.

At least 300,000 people had been told to leave San Diego county, where hundreds of homes have been destroyed.

The state of emergency opens the way for federal government assistance.

The US president, George Bush, today authorised the Federal Emergency Management Agency - the body heavily criticised for its response to Hurricane Katrina - to coordinate disaster relief in the seven worst affected counties.

One firefighter described the scene as looking like a "nuclear winter". Conditions were expected to get worse, with temperatures of up to 38C expected in parts of southern California and desert winds of up to 70mph fanning the flames across the tinder-dry region.

At least 1,000 homes have so far been destroyed and thousands more are under threat from the 14 major fires burning across the state.

Neighbouring states including Nevada and Arizona are contributing crews and equipment, and the Pentagon is sending six water-dropping planes to help with the effort.

At least one person has been killed in the fires. He was named by the Associated Press news agency as Thomas Varshock, 52, of Tecate, a town on the Mexican border south-east of San Diego.

"Lifesaving is our priority. Getting people out from in front of the fire - those have been our priorities," Captain Don Camp, from the California department of forestry and fire protection, said.

A pair of wildfires consumed 128 homes in the mountain resort area of Lake Arrowhead, in the San Bernardino national forest east of Los Angeles.

"We're stretched very thin and we can't get any planes up," John Miller, a forest spokesman, said. State officials called in the National Guard.

Air quality plummeted as winds of up to 90mph deposited ash and soot across the area. Low brown clouds darkened the skies on what would have been a clear, sunny day.

Power lines brought down by the high winds were thought to be responsible for sparking the fires at the weekend, although fire officials blamed arsonists for some of the fiercest blazes, in Orange county, south of Los Angeles.

Local television stations turned their schedules over to cover the fires, with helicopter shots showing lines of fire snaking across the canyons that reach inland from the Pacific Ocean.

The flames stretched from the Mexican border to Santa Barbara county, almost 200 miles to the north. Some 16,200 hectares (40,000 acres) had been burned by yesterday morning, forcing the evacuation of thousands of residents and the closure of schools in several areas.

In Malibu, where 1,500 residents were evacuated, a church was destroyed by fire - as was a mock turreted "Scottish" castle, an ornate local landmark that was on the market for $17m (£8.3m).

The building's owner, Lilly Lawrence, the daughter of a former Iranian oil minister, took mementoes, including Elvis Presley's army fatigues, to safety.

"My parents taught me not to allow my possessions to possess me," she told local TV. "So, that's the story. The house is a house."

News pictures showed some of the rich and famous of Malibu, including the film producer Jeffrey Katzenberg, dousing their homes with fire retardant.

The fierce winds, which calmed overnight on Sunday but picked up yesterday morning, carried burning embers across the Pacific Coast highway towards the exclusive beachfront properties.

"We're at the mercy of the wind," Malibu's mayor, Pamela Conley Ulich, told reporters on Sunday night. Firefighters yesterday estimated that the blaze was only 10% contained.

The brush fires, fuelled by the Santa Ana desert winds, are an annual event in southern California.

The Santa Anas carry warm air from the desert to the coast, drying out the land as they pass and spreading the fires. Despite recent rains, southern California, like all the western US, is experiencing a severe drought.

"This was a conflagration that we knew was coming at some point," the Los Angeles county supervisor, Zev Yaroslavsky, told reporters.